Diabetes Mellitus is the most common medical complication of pregnancy. GDM is associated with increased fetal and maternal morbidity, and women with history of GDM are at increased risk for subsequent development of type 2 diabetes mellitus probably because both conditions share common risk factors. In addition the children of women who had GDM are at increased risk for obesity, glucose intolerance, and diabetes during adulthood. This causes a cycle of increased glucose intolerance in the population. So, detection of women at higher risk for GDM early in pregnancy is a desirable goal because interventions such as diet, exercise and medication may be applied earlier in pregnancy and potentially can reduce later development of GDM or its associated morbidities. This study was conducted on 100 single-tone pregnant women with gestational age 8−12 weeks. We excluded any pregnant patient with known diabetes or history of any medical disorder. Full history taking, complete general and abdominal examination and Ultrasonography were done. HbA1c, fasting & 2h postprandial blood sugar were done for all patients. Then all patients underwent routine GDM screening with 50 gm 1-hour oral glucose challenge test (GCT) between 24−28 weeks gestation. Patients with plasma glucose level ≥140mg/dl underwent 100-g, 3-hour diagnostic oral glucose tolerance test (OGTT). Patients were classified into two groups according to development of gestational diabetes mellitus into GDM group and Normal group. The two groups were compared according to the presence of any risk factors make them susceptible for the development of gestational diabetes mellitus as age, high BMI, gravidity, parity, positive family history of diabetes mellitus(first degree relatives), previous gestational diabetes mellitus, previous high birth weight babies(≥4kg), previous intra-uterine fetal death(IUFD), previous baby with congenital anomalies, recurrent pregnancy loss. Also compared for first trimester fasting blood sugar value, HbA1c % and number of risk factors in each patient. Also, outcome of the current pregnancy was compared in both groups as development of hypertension with pregnancy, type of delivery, birth weight and neonatal ICU admission.